The present invention relates to a steam-heating apparatus in which a heating section formed in a heat exchanger is connected with a steam supply pipe for receiving supply of heating steam and connected also with a condensate recovering unit for discharging condensate produced as a result of heating.
An example of such steam-heating apparatus is known from Japanese paten application laid-open No. Hei. 7-328423. In this steam-heating apparatus, as shown in FIG. 6, a reaction vessel 1 is provided as a heat exchanger. The reaction vessel includes, as a heating section thereof, a jacket section 2, to which a steam supply pipe 3 for receiving supply of heating steam and a condensate recovering unit 6 for discharging condensate produced as a result of heating are connected. More particularly, the steam supply pipe 3 is connected to an inlet of a steam ejector 5 and the jacket section 5 as a heating section is connected to a suction chamber 13 formed in an outer periphery of a nozzle communicated with the inlet of the steam ejector 5. Also, a shutoff valve 47 is connected to an outlet communicated with the suction chamber 13.
In operation, by opening the shutoff valve 47, air remaining within the jacket section 2 will be drawn into the suction chamber 13 to evacuate the inside of the jacket section 2. Thereafter, by dosing the shutoff valve 47, low-pressure steam is supplied into the jacket section 2, so that an object in the reaction vessel 1 may be heated by low-temperature steam of 100xc2x0 C. or lower.
With the conventional steam-heating apparatus described above, the apparatus is capable of steam-heating an object with the air remaining at the initial stage of the heating process being removed by suction. However, this apparatus cannot exhaust air which may be gradually accumulated with progress of the heating process, so that the apparatus becomes unable to maintain a predetermined heating temperature precisely. Specifically, when the heating apparatus is placed under the evacuated condition below the atmospheric pressure, atmospheric air may be inadvertently drawn through in the respective joints of the apparatus, thus leading to gradual accumulation of air inside the heating section. Moreover, the heating steam supplied to the apparatus may contain some air therein. Therefore, disadvantageous accumulation of air inside the heating section occurs not only in the initial stage of the heating process but also during the subsequent heating stage thereof
Accordingly, an object of the present invention is to provide a steam-heating apparatus capable of adjusting the heating temperature with high precision by effectively eliminating air which may be accumulated not only in the initial stage of the steam-heating process but also during the subsequent heating stage thereof.
For accomplishing the object noted above, a steam-heating apparatus proposed by the present invention comprises a steam ejector including a suction chamber connected to the heating section and an inlet for receiving supply of heating steam, the steam ejector being actuated in response to a drop in a temperature of the heating section by a predetermined value so as to suck air (an example of gas) in the heating section into the suction chamber of the steam ejector
That is, in response a drop by a predetermined value in the temperature in e.g. the heating section or in a condensate tank disposed between this heating section and the condensate recovering device, the steam ejector is actuated and steam is supplied to the inlet of the steam ejector, whereby a suction force is developed in the suction chamber for sucking the air accumulated in the heating section therein and subsequently exhausting this air to the outside.
Therefore, in the steam-heating apparatus, whenever the temperature of the heating section drops by a predetermined value due to presence of air therein not only in the initial stage of heating, but also during subsequent heating stage thereof, the steam ejector is actuated for sucking and exhausting this air.
Further, in addition to the above-described construction of the steam-heating apparatus, the steam-heating apparatus of the invention may filer comprise a temperature-responsive valve disposed at the inlet of the steam ejector, the temperature-responsive valve being opened in response to the drop by the predetermined value of the temperature of the heating section so as to supply the steam to the inlet of the steam ejector.
That is, by providing the temperature-responsive valve connected to the inlet of the steam ejector, when air has accumulated in the heating section to cause the temperature thereof to drop by a predetermined value, the temperature-responsive valve is opened to introduce steam into the inlet of the steam ejector and the air accumulated in the heating section is withdrawn by the resultant suction force developed in the suction chamber to be exhausted to the outside.
In addition to the above-described construction of the steam-heating apparatus, the steam-heating apparatus of the invention may further comprise a check valve disposed at a connection between the heating section and the suction chamber of the steam ejector, the check valve allowing only unidirectional passage of the air from the heating section to the suction chamber of the steam ejector.
That is, by providing the check valve disposed between the suction chamber of the steam ejector and the heating section or the condensate tank in addition to the temperature-responsive valve connected to the inlet of the steam ejector, when the temperature drops by a predetermined value as a result of accumulation of air inside the heating section or the condensate tank, the temperature-responsive valve is opened to supply steam to the inlet of the steam ejector and the check valve is opened by the resultant suction force of the steam ejector to allow communication of air from the heating section to the suction chamber thereby to suck and exhaust the air accumulated inside the heating section to the outside.
Further, the steam-heating apparatus of the present invention, in addition to the above-described construction of the steam-heating apparatus, further comprises a temperature-responsive valve disposed at a connection between the heating section and the suction chamber of the steam ejector, the temperature-responsive valve being opened in response to a drop by a predetermined value in the temperature of the heating section so as to allow suction of the air from the heating section to the suction chamber of the steam ejector.
That is, by providing a temperature-responsive valve disposed at a connection between the heating section and the suction chamber of the steam ejector, when air has accumulated inside the heating section thus causing a drop in its temperature by a predetermined value, the temperature-responsive valve is opened to establish communication between the heating section and the suction chamber of the steam ejector, whereby the air accumulated in the heating section can be sucked and exhausted to the outside by the resultant suction force developed in the suction chamber.
For accomplishing the object of this invention, the steam-heating apparatus of the present invention comprises a condensate tank disposed between the eating section and the condensate recovering unit and a steam ejector having a suction chamber connected to the heating section or to the condensate tank and an inlet for receiving supply of steam, the steam ejector being actuated in response to a drop by a predetermined value in the temperature inside the heating section or the condensate tank so as to suck air in the heating section or the condensate tank into the suction chamber of the steam ejector.
That is, when the temperature inside the heating section or the condensate tank interposed between the heating section and the condensate recovering unit drops by a predetermined value, the steam ejector is actuated to cause the air in the heating section or the condensate tank to be sucked into the suction chamber of the steam ejector. With this, when air has accumulated inside the heating section and the condensate tank resulting in a temperature drop by a predetermined value, the steam ejector is actuated so that steam is supplied to the inlet of the steam ejector from e.g. a steam supply pipe an the resultant suction force developed in the suction chamber can suck the air accumulated inside the heating section and the condensate tank and exhaust the air to the outside.
Accordingly, in the steam-heating apparatus, both in the initial stage of heating and during the subsequent heating stage, whenever air has accumulated inside the heating section or the condensate tank thus resulting in such temperature drop, the steam ejector is actuated to suck and exhaust the air.
Further, the steam-heating apparatus of this invention, in addition to the above-described construction of the steam-heating apparatus, further comprises a temperature-responsive valve disposed at the inlet of the steam ejector, the temperature-responsive valve being opened in response to a drop by a predetermined value in the temperature inside the heating section or the condensate tank so as to supply the steam of the steam supply pipe to the inlet of the steam ejector.
That is to say, m case the steam-heating apparatus includes a condensate tank, there is provided the temperature-responsive valve connected to the inlet of the steam ejector. With this, when air has accumulated inside the heating section or the condensate tank resulting in a temperature drop by a predetermined value, the temperature-responsive valve is opened so as to supply steam to the inlet of the steam ejector and a suction force is developed in the suction chamber. With this, the air accumulated in the heating section and the condensate tank may be sucked into the suction chamber via a check valve or the like provided between the suction chamber of the steam ejector and the condensate tank and the air may be exhausted to the outside subsequently.
Further, the steam-heating apparatus of the present invention, in addition to the above-described construction of the steam-heating apparatus, further comprises a check valve provided at a connection between the heating section or the condensate tank and the suction chamber of the steam ejector, the check valve allowing only unidirectional gas passage from the heating section or the condensate tank to the suction chamber of the steam ejector.
That is, by providing a check valve between the suction chamber of the steam ejector and the heating section or the condensate tank in addition to the temperature-responsive valve connected to the inlet of the steam ejector, when air has accumulated inside the heating section or the condensate tank thus resulting in a drop in its temperature by a predetermined value, the temperature-responsive valve is opened to supply steam to the inlet of the steam ejector and the check valve is opened by the resultant suction force from the steam ejector so as to allow communication of air from the heating section or the condensate tank to the suction chamber, so that the air accumulated inside the heating section or the condensate tank may be sucked and exhausted to the outside by the suction force in the suction chamber.
For accomplishing the object of this invention, with the steam-heating apparatus of the present invention, the condensate recovering unit includes a high-pressure control fluid inlet for receiving supply of high-pressure control fluid for pressure-transporting and discharging the condensate, the apparatus comprises an ejector including a suction chamber connected to the heating section, an inlet for receiving supply of the high-pressure control fluid and an outlet connected to the high-pressure control fluid inlet and further comprises a valve means provided at a connection between the heating section and the suction chamber of the steam ejector.
That is to say, the ejector is incorporated in a high-pressure control fluid passage for passing the high-pressure control fluid; the outlet of the ejector is connected to the high-pressure control fluid inlet of the condensate recovering unit; and the suction chamber of the ejector and the heating section are connected to each other via the valve means comprising e.g. a shutoff valve. In operation, when the high-pressure control fluid is introduced into the condensate recovering unit thereby to pass the high-pressure control fluid through the ejector, a suction force is developed in the suction chamber of the ejector, whereby air accumulated inside the heating section may by sucked and exhausted via the valve means.
Accordingly, both in the initial stage of the heating and the subsequent heating stage, each time the high-pressure control fluid is introduced into the condensate recovering unit, a suction force is developed in the ejector, so that the air accumulated in the heating section may be eliminated.
For accomplishing the object of this invention, with the steam-heating apparatus of the present invention, the condensate recovering unit includes a high-pressure control fluid inlet for receiving supply of high-pressure control fluid for pressure-transporting and exhausting the condensate and a condensate returning outlet for exhausting the pressure-transported condensate, the apparatus comprises an ejector including a suction chamber connected to the heating section and an inlet connected to the condensate returning outlet, and the apparatus further comprises a valve means provided at a connection between the heating section and the suction chamber of the steam ejector.
That is to say, the ejector is incorporated in a high-pressure control fluid passage connected to the condensate returning outlet of the condensate recovering unit and the suction chamber of the ejector and the heating section are connected to each other via the valve means comprising e.g. a shutoff valve. In operation, when the high-pressure control fluid is introduced from the condensate pressure-transporting passage thereby to pass the condensate through the ejector, a suction force is developed in the suction chamber of the ejector, whereby air accumulated inside the heating section may by sucked and exhausted via the valve means.
During both the initial stage of the heating process and the subsequent heating stage of the same, a suction force is developed in the ejector every time the condensate is pressure-transported from the condensate pressure-transporting passage of the condensate recovering unit, whereby air accumulated inside the heating section may be sucked and exhausted,
Further, with the steam-heating apparatus of the present invention, in addition to the above-described construction, the valve means comprises a temperature-responsive valve which is opened in response to a drop in the temperature by a predetermined value in the heating section or between the heating section or the condensate recovering unit so as to allow suction of air from the heating section into the suction chamber of the ejector.
That is to say, when the temperature in the heating section or between the heating section and the condensate recovering unit, such as the condensate tank, drops by a predetermined value, the temperature-responsive valve as the valve means is opened to establish communication between the heating section and the suction chamber of the steam ejector, so that the resultant suction force developed in the suction chamber sucks and exhausts the air accumulated inside the heating section to the outside.